It is well established that bacteria-carrying particles and epithelial scales are released continuously from the human body and that it is essential, in order to avoid as far as possible cross contamination of patients by operating theatre personnel, to take precautions to rid the atmosphere of operating theatres of such particles and scales. As part of the precautions relative thereto, conditioning of the air in operating theatres and/or in the immediate vicinity of operating tables is generally practised. Also, operating theatre personnel are required to wear all-enveloping gown-and-hood arrangements incorporating means adapted for connection to an air exhaust system. When such an arrangement is used, all airborne emissions within the gown and hood are drawn into the exhaust system by an air current such that the interior of the gown is maintained at a negative pressure and ambient air flows into the gown, usually from below. The material of the gown, is, of course, chosen so as to be an effective barrier to the passage of air and airborne emissions.
All previously proposed all-enveloping gown-and-hood arrangements of this type, as described, for example, in British Patent Specifications Nos. 1208284 and 1395099 have incorporated some form of rigid face mask or visor as well as some form of exhaust inlet to draw air from the region of the wearer's face. Such arrangements have proved cumbersome and uncomfortable to wear and have often given rise to difficulties in communication due to the physical barrier of the mask or visor and/or the noise of air being exhausted adjacent the face of the wearer. Indeed, expensive audio communication systems have sometimes been required to overcome the latter difficulty.